EdgeEndo : Tip Evaluation (1st 3mm)

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DETAILS:

FILE NAME: EdgeFile
COMPANY: EdgeEndo
MANUFACTURER: MicroMega
MADE IN: France
HEAT TREATED IN: United States by US Endo
WEBSITE: edgeendo.com

 

CHARACTERISTICS:

SIZE: 25/04
FLUTES: 3 (triangular)
SPIRALS PER 16MM: 6
HELIX ANGLE: 26º [fig. 2]
CUTTING ANGLE: (-) 40º [fig. 1]
DEBRIS REMOVING AREA: 60% [fig. 1]
ROTATION TO FAILURE: 1002º
PEAK TORQUE AT FAILURE: 51.13 gf/cm
60 ̊ DEFLECTION: 1.62 g
PLASTIC DEFORMATION: 7º
FILE CORE AREA RELATIVE TO CIRCUMFERENCE AREA: 32%
FILE CORE AREA RELATIVE TO FILE X-SECTION AREA: 60%

 

DISCUSSION:

  • Although the file is very flexible, its resistance to torsional stress is very limited. Plastic deformation occurs with comparatively minimal force.
  • The tip is blunt and will not negotiate a canal having a smaller diameter without burnishing its way into the canal and resulting in greater torsional stress.
  • The large number of spirals requires debris to be conveyed a greater distance and increases the EdgeEndo’s tendency to screw into the canal. Both factors contribute to increasing torsional stress.

 

TIP SEM

Fig. 1 : TIP X-SECTION

Fig. 2

 

 

 

 

 

 

 

 

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One Endo : Tip Evaluation (1st 3mm)

DETAILS:

FILE NAME: One Endo
COMPANY: NanoEndo
MANUFACTURER: D&S Dental
MADE IN: USA
WEBSITE: nanoendo.com

 

CHARACTERISTICS:

SIZE: 25/04
FLUTES: 2 (S-shape, H-type)
SPIRALS PER 16MM: 3.5
HELIX ANGLE: 7.5º [fig. 2]
CUTTING ANGLE: (-) 40º [fig. 1]
DEBRIS REMOVING AREA: 38% [fig. 1]
ROTATION TO FAILURE: 510º
PEAK TORQUE AT FAILURE: 86.81 gf/cm
60 ̊ DEFLECTION: 3.56 g
PLASTIC DEFORMATION: 0º
FILE CORE AREA RELATIVE TO CIRCUMFERENCE AREA: 43%
FILE CORE AREA RELATIVE TO FILE X-SECTION AREA: 65%

 

DISCUSSION:

  • The degree rotation to failure is less than that for the Edge file or the ESX.
  • The peak torque at failure is more than the Edge but less than the ESX.
  • Interestingly, the One Endo was not superior in either the rotation to failure or deflection tests but was the only file that did not fail the Endo File Evaluator protocol. This is likely due to the One Endo’s blade that extends closer to its actual tip and the single blade opposed by a rounded surface and its reduced helix angle. These features facilitate greater efficiency in debris removal.

 

TIP SEM

Fig. 1 : TIP X-SECTION

Fig. 2

 

 

 

 

 

 

 

 

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Sequence ESX : Tip Evaluation (1st 3mm)

DETAILS:

FILE NAME: Sequence ESX
COMPANY: Brasseler USA
MANUFACTURER: FKG
MADE IN: Switzerland
WEBSITE: brasselerusadental.com

 

CHARACTERISTICS:

SIZE: 25/04
FLUTES: 3 (triangular)
SPIRALS PER 16MM: 2.67
HELIX ANGLE: 9.5º [fig. 2]
CUTTING ANGLE: (-) 30º [fig. 1]
DEBRIS REMOVING AREA: 55% [fig. 1]
ROTATION TO FAILURE: 560º
PEAK TORQUE AT FAILURE: 88.57 gf/cm
60 ̊ DEFLECTION: 2.32 g
PLASTIC DEFORMATION: 0º
FILE CORE AREA RELATIVE TO CIRCUMFERENCE AREA: 28%
FILE CORE AREA RELATIVE TO FILE X-SECTION AREA: 62%

 

DISCUSSION:

  • Manufacturer claims a booster tip comprised of 6 cutting sides but its sides are so small that they actually form a non-cutting tip. The tip will not negotiate a canal having a smaller diameter without burnishing its way into the canal and resulting in greater torsional stress.
  • The finish is excellent and the blades are sharp.
  • Testing shows the recommendation of using 2-3 files is overly ambitious as is the recommended use of long strokes for insertion.

TIP SEM

Fig. 1 : TIP X-SECTION

Fig. 2

 

 

 

 

 

 

 

 

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Descriptions of Protocols and Terminology

Rake & Cutting Angle:
If the file is sectioned perpendicular to its long axis, the rake angle (cutting angle) is the angle formed by the leading edge and the radius of the file inscribed in its circle of rotation. While using the radius as the line of reference, if the leading edge is in front of the perpendicular radius, it is referred to as a negative (scraping) cutting angle and is measured as the angle formed by the leading edge and radius. If the leading edge is behind the radius, it is referred to as a positive cutting angle.

Negative Angle

X-Section with Negative Angle

X-Section with Positive Angle

X-Section with Positive Angle

 

 

 

 

 

 

 


 

Circumference Area & Core Area:
The circumference area (A=3.14r²), inscribed by the rotation a file, is determined by defining r as the distance from the file’s central axis of rotation to the file’s outer most boundary. The core area of the file (A=3.14r²) is the cylindrical center area of the file having its circumference outlined and bordered by the depth of its flutes. It should be noted that there are instances when the central axis of rotation is separate from the file core’s center.

File with symmetrical X-section

File with Symmetrical X-Section

File with Asymmetrical X-Section

File with Asymmetrical X-Section

Circumference&AreaKey

 

 

 

 

 

 


 

FLUTES & SPIRALS:
The flute of the file is the groove in the working surface used to collect soft tissue and dentine chips removed from the wall of the canal. The surface having the greatest diameter that follows the groove (defined as where the flutes intersect), as it rotates, forms the leading (cutting) edge. The number of spirals that a file has in its working surface can be calculated by dividing the number of flutes on the working surface by the number of flutes in  x-section.

Sides of X-Section Point to Corresponding Flutes

Sides of X-Section Point to Corresponding Flutes

 

 

 

 

 

 

 

 

 


 

HELIX ANGLE:
The helix angle is the angle the blade makes as it intersects with central longitudinal axis of the file.

Helix Angle

Helix Angle

 

 

 

 


 

DEBRIS REMOVING AREA:
The debris removing area is the total flute space represented as a percentage of the circle area that inscribes the file.

DebrisRemovalArea

 

 

 

 


 

DEFLECTION & DEFORMATION:
Deflection is measured as the file is lowered 5mm onto a 60 degree incline. If the file remains bent as it is lifted from the incline, the angle of the bend is measured as plastic deformation.

Deflection

 

 

 

 

 

 

 


 

ROTATION TO FAILURE:
To determine rotation to failure, 3mm of the tip end of a file is locked into place before rotating its handle end continuously until it breaks. The degree of total rotation is measured at the point where the file fails.


 

PEAK TORQUE AT FAILURE:
Peak torque at failure describes the maximum torque the file undergoes as it is rotated to failure.


 

 

 

Introduction to Mastering Endodontic Instrumentation : An online addendum

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What differences do design differences make? We intend to find out. We are embarking on a very ambitious research program to test each part of every major file in production, from tip to handle. We have completely up-dated the computer controlled Endo File Evaluator to improve resolution of its sensors and motors and to expand its capability for performing new testing protocols. As such, we have created what I believe is not only the most objective means for evaluating endodontic files, but also the best method for testing file functions in a manner that is truly relevant within a clinical setting. We do this while letting the data determine the results for objective comparisons independent of operator skill or marketing bias.

What difference does this endeavor make? Our first objective is to finally determine how to minimize risk and maximize efficiency, how file designs relate to function, how function relates to canal anatomy, and how anatomy relates to technique. Our second objective is to present the Endo File Evaluator results using the numerous different parameters for testing, and to use high resolution images and SEMs in a manner that allows clinicians to save and apply the information to enhance their skill and treatment.

How will this process take place? About every ten days we will share test results and observations of only one segment of each file beginning with the file tips. Through this blog, we invite you to participate in discussions and critiques to create group research dynamics as this project progresses. Once all segments of the files have been covered, a composite of each whole file will be available as an endodontic reference along  with any contributing assessments gathered from our readers. We will continue providing results as we find them through this comprehensive series of evaluations and add to them in the future as needed. We are excited to embark on this endeavor and hope you will follow along and contribute your own thoughts and impressions.

 

DOWNLOAD MASTERING ENDODONTIC INSTRUMENTATION (original award winning text)